The invention relates to a tamper resistant closure attachment accessory to a machine for wrapping a ribbon around the gathered neck of a bag and twisting the ribbon for closing and sealing the neck of the flexible bag.
U.S. Pat. No. 3,138,904 entitled xe2x80x9cMETHOD AND APPARATUS FOR TYING PACKAGES AND WRAPPING MATERIALS;xe2x80x9d U.S. Pat. No. 3,059,670 entitled xe2x80x9cWIRE TWISTING TOOL;xe2x80x9d U.S. Pat. No. 3,919,829 entitled xe2x80x9cAPPARATUS FOR TYING PACKAGES AND WRAPPING MATERIALS;xe2x80x9d U.S. Pat. No. 4,856,258 entitled xe2x80x9cWIRE TYING DEVICE;xe2x80x9d and U.S. Pat. No. 5,483,134 entitled xe2x80x9cRIBBON SENSING DEVICE FOR BAG TYERxe2x80x9d disclose apparatus used for closing a plastic bag by attaching and twisting a wire-like ribbon about the neck of the bag.
Bag tying devices of the type disclosed in the aforementioned patents are commercially available from Burford Corporation of Maysville, Okla. The tying devices are generally constructed to receive packages such as loaves of bread at speeds of for example over one hundred (100) packages per minute at speeds of about 108 feet per minute.
Plastic bags containing bakery products, paper plates and ice are easily opened by removing the twisted ribbon from about the neck of the bag so that the contents of the bag are accessible. The bag can be resealed by manually replacing and twisting the ribbon about the neck of the bag.
U.S. Pat. No. 5,600,938 discloses apparatus for sealing a plurality of spaced spots across the flattened open end of a filled plastic bag. The bag is moved along a conveyor past a sealing mechanism where a plurality of spaced spots are welded or fused across the open end of the bag. In one embodiment a sealing mechanism includes a plurality of heated pins which penetrate the two layers of the open end of the bag while the end of the bag is substantially flat. These pins then move along with the bag in synchronism with the conveyor while the fusing occurs. In another embodiment, the sealing is accomplished by using a wheel having heated pins around its periphery and the wheel is rotated so that its tangential speed is in synchronism with the conveyor to successively make spaced fused spots across the generally flat open end of the bag. The apparatus seals a plurality of spaced spots to only delicately seal the bag to show evidence of tampering by breaking the seal but allow the bag to be opened without tearing or destroying the bag.
U.S. Pat. No. 5,741,075 describes a package comprising a flexible plastic bag and a label, the bag having a closed end, the closed end being openable to provide an opening for access to the contents of the package, wherein, the closed end of the package is initially sealed at a sealing area and, wherein, the sealing area is provided with a line of perforations to define the opening and reclosable by means of the label. The label is disclosed as having on one face two areas of adhesive separated by a non-adhesive area extending across substantially the whole width of the label, the adhesive areas being adapted to adhere to the package, one to each side of the line of perforations. A satisfactory method and apparatus for forming the seal and the line of perforations to provide an initial tamper-evident tear-off strip is not disclosed.
Heretofore, no system has been devised for forming a reclosable tamper-proof seal which can be economically applied for safe-guarding the contents of the bag prior to its being opened by the ultimate consumer.
The apparatus disclosed herein is used to form a tamper resistant seal on plastic bags wherein the sides of the bag are welded together for forming a seal adjacent a row of perforations formed in the bag to facilitate tearing the seal from the bag to gain access to the contents. After the seal and perforated strip have been formed on the bag the neck of the bag is gathered and tied by twisting a wire-like ribbon about the neck of the bag.
The apparatus for forming the tamper resistant seal is preferably mounted on a bag tyer, for example of the type disclosed in U.S. Pat. No. 5,483,134, the disclosure of which is incorporated herein by reference in its entirety for all purposes. Gathering belts are mounted on pulleys synchronized with the gathering belts in the bag neck tying device.
The bag neck is flattened adjacent the gathering belts and the flattened bag neck moves adjacent a roller which has projections for forming a row of perforations in the neck of the bag. The bag moves between a pair of manifolds through which heated air flows to impinge against upper and lower surfaces of the bag neck for sealing the bag. The manifolds do not contact the surface of the bag such that the bag neck can be sealed even though printing ink on the surface of the bag may not have dried or cured or if the heat softens the ink.
Once the seal and row of perforations have been formed on the bag, the neck of the bag moves through the tying device where the neck of the bag is gathered, tied and ejected from the tying device in conventional manner.
It should be readily appreciated that in lieu of a twisted wire tie around the gathered neck, other closure means such as plastic wireless twist ties, plastic clips having a slot or adhesive tape may be attached to the gathered neck of the bag. The closure seals the bag between the row of perforations and the contents to prevent contamination and for maintaining freshness of the contents of the bag.